The present invention relates to testing packet data signal transceiver devices under test (DUTs), and in particular, to using a shared packet data signal source to test multiple DUTs capable of communicating using multiple radio access technologies (RATs).
Many of today's electronic devices use wireless technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless technologies must adhere to various wireless technology standard specifications.
When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless technology standard-based specifications.
For testing these devices following their manufacture and assembly, current wireless device test systems employ a subsystem for analyzing signals received from each device. Such subsystems typically include at least a vector signal generator (VSG) for providing the source signals to be transmitted to the device under test, and a vector signal analyzer (VSA) for analyzing signals produced by the device under test. The production of test signals by the VSG and signal analysis performed by the VSA are generally programmable so as to allow each to be used for testing a variety of devices for adherence to a variety of wireless technology standards with differing frequency ranges, bandwidths and signal modulation characteristics.
As part of the manufacturing of wireless communication devices, one significant component of production cost is costs associated with manufacturing tests, particularly with many such devices being manufactured at the rate of millions of devices per month. Typically, there is a direct correlation between the cost of test and the sophistication of the test equipment required to perform the test. Hence, innovations that can preserve test accuracy while minimizing equipment costs (e.g., due to rising costs of increasingly sophisticated test equipment, or testers) are important and can provide significant costs savings.
Testing of such wireless DUTs can be done faster by testing multiple DUTs concurrently. One technique includes using multiple test systems, or testers, with each one connected to its own DUT and operating essentially in parallel. Another technique includes sharing test equipment resources in such a way that multiple DUTs, following initialization and synchronization, receive a sequence of replicated test waveforms. This technique can be used where the DUTs are all receiving the same waveforms and are testing the same radio access technology (RAT). In those cases where the multiple DUTs are being tested for different RATs, and the download (DL) test packets have different characteristics (e.g., bit content, packet length, packet duration, etc.), a test waveform generator (e.g., a VSG) can only source one waveform at a time for a particular RAT test. As the DUTs being tested for different RATs are switched or multiplexed to receive the signal from the single test waveform generator, test continuity and integrity will be lost unless operation of each DUT is appropriately synchronized with the test waveform it is to receive. Therefore, concurrent DUT testing has been limited to cases where multiple DUTs are all being tested for the same RAT.
Accordingly, it would be desirable to have a technique for concurrent testing of increasingly sophisticated DUTs with increasingly varied performance characteristics and requirements without also requiring increasingly sophisticated testers with similarly increasingly varied testing characteristics and requirements.